Fuel-supply system



Jan. 28, 1964 c CUMMINS,'JR 3,119,381

FUEL-SUPPLY SYSTEM Filed Jan. 4, 1962 INVENTOE CLESJIE L. cuMM/Ms; JE.

By W 4 5 L H United States Patent M 3,119,331 FUEL-EsiJPPLY SYSTEMlessie Lyle Cummins, lira, Mill Valley, Calif., assignor to Clessie L.Cummins, Sausalito, Calif. Filed Jan. 4, B62, Ser. No. 164,284 19Claims. (Cl. 12314il) This invention relates to a fuel-supply system forcompression-ignition inte nal-combustion engines more particularly to afuel-measuring pump of the positive d1splacement type for engines.

Even though the inherent economic and safety advantages of thecompression-ignition or diesel-type engines are well recognized, therehas been little success in developing a compact and reliable dieselengine which could be used, for example, in an outboard type of enginefor marine use. One of the major reasons for this failure is the lack ofan inexpensive but satisfactory fuel system. In the past diesel fuelsystems have been relatively bulky and did not lend themselves to areduction in size as the engine itself became smaller.

It is, therefore, an important object of this invention to provide acompact, inexpensive and easily serviced fuelsupply pump for dieselengines, including small, lightweight diesel engines.

While the fuel supply system lends itself to the small, marine enginefield, it is to be understood that the invention can be applied also todiesel engines used in many other types of service, such as generatorsets, earth-moving equipment, air compressors, automotive vehicles, etc.

Another object of the invention is to eliminate the need for rotatingcamshafts and complicated levers and rollers in positive displacementfuel pumps and also to get better results from a simplified device. Theinvention provides a metering mechanism utilizing a hydraulicallyactuated metering piston with a fixed stroke-the only oscillating partof the fuel feeding system. Costs are reduced, and part lives areextended.

Other objects and advantages will appear from the following descriptionand the attached drawings in which:

FIG. 1 is a schematic view partly in cross-section of a fuel supplysystem embodying the principles of the invention;

PEG. 2 is a fragmentary view of a portion of the device of FIG. 1showing the rotor-plunger rotated 180 from the position shown in FIG. 1and distributing a fuel charge to the other of the two injectors;

FIG. 3 is a fragmentary view of a portion of a modified device generallysimilar to that of FIG. 1, but with the rotor-piunger in a modified typeof housing and adapted to pump a fuel charge into a conduit leading totwo paired injectors of a two-cycle engine;

FIG. 4- is a fragmentary view of a portion of the device of FIG. 1showing the rotor-plunger in its idling speed position;

FIG. 5 is a schematic view partly in section of a portion of a modifiedform of fuel system embodying the principles of the invention;

FIG. 6 is a view in section of the distributor of FIG. 5 taken on theline VIVI, showing a distributor for a six cylinder engine;

FIG. 7 is a fragmentary view of a portion of a modified form of fuelsystem also embodying the principles of the invention.

Important Characteristics of the Invention Before giving a detailedexplanation of the invention, I should like to summarize in generalterms some of its outstanding characteristics.

The invention provides, in a fuel system for a diesel engine, afree-ioating shuttle piston reciprocable between fixed stops in acylinder. The cylinder is ported at each sgnassi Patented Jan. 28, 13954- end so that the pressurized fuel acts alternately on each end ofthe piston; so the pressurized fuel serves as the source of hydraulicpower to operate the mechanism. There is no mechanical connectionbetween the shuttle piston and the fuel-pump drive of the engine.

Fixed stops at each end of the cylinder limit the movement of theshuttle piston and so determine the maximum fuel charge delivered to thefuel injector. Therefore the maximum horsepower output of the engine isdependent on the distance between these fixed stops, and the maximumoutput can only be changed by increasing or decreasing this distance.One of the stops may be a replaceable unit (or, if desired, may beadjustable) so that, with the proper extension on the stop, variousratings of engines can be obtained from the same pump.

The invention provides in a two or four-cycle diesel engine of a compactcylindrical rotor-plunger, rotated at engine speed or at a speed bearinga fixed ratio to engine speed, the ratio being dependent on the numberof engine cylinders and on the cycle type. The ported cylinder for theshuttle piston may be axially located within the rotor-plunger. Thisrotor-plunger is also slidably fitted in a bore in the pump housing andis positioned along the bore by engine-speed-created forces balancedagainst counterbalancing springs. The rotor-plunger rotates in order toconnect the ported chamber on one end of the shuttle piston to thefuel-receiving chamber in a mechanically actuated injector at the sametime that the ported chamber on the opposite end of the shuttle pistonis connected to the pressurized fuel, so that the charge of fuel in thefirst-named ported chamber may be pumped to the fuel-receiving chamberin the injector. The rotorplungers axial position in its bore,determined by the balance of forces acting on each end of the rotor,controls the minimum and maximum speeds of the engine, as well as therate of fuel delivery at all intervals between the two speed ranges.

In the above-stated combination the relationship betweencounterbalancing springs and'a manually operated throttle stop actingagainst the end of the springs, enables the rotation of the throttleshaft to effect an increase or decrease in the force of the springsacting against the end of the rotor-plunger, whereby for a given enginespeed the axial position of the rotor-plunger is determined by theposition of the throttle shaft. The unwanted portion of the fuel chargenormally sent from the fixed-volume ported chambers to the fuelreceiving chamber in one of the injectors, is spilled off and returnedto the fuel source.

The invention also provides, in combination with the slidably mountedand rotating cylindrical rotor-plunger a second rotor, turning atcamshaft speed (for a four-cycle engine), which receives the chargesfrom the rotorplunger and distributes them to the fuel receivingchambers in mechanically actuated injectors in a properly timedsequence.

In some forms of the invention, there is the combination in a dieselengine having the mechanically actuated injectors, each with its fuelreceiving chamber, of the slidably positioned cylindrical rotor-plunger,with its fuelfeeding ports connected so that one conduit from one portleads to two or more of the fuel receiving chambers; the rotor is intimed relation to the injectors so that only one of the fuel receivingchambers can receive a charge during the pumping stroke of the shuttlepiston.

The Source of Pressurized Fuel for Combustion and for HydraulicOperation of the Metering Mechanism (FIG. 1)

the crankshaft. Fuel for the engine is adapted to be drawn from a tank2%) through a conduit 21, a primary filter 22, and a conduit 23 to anengine driven pump 24, herein illustrated as a gear pump turning atcrankshaft speed.

Fuel under pressure from the pump 24 flows through a conduit 25 and asecondary filter 26 to a pressure regulator 27. Spill off from theregulator 27 passes back through conduits 28 and 23 to the suction sideof the pump 24. It is the function of the regulator 27 to maintain asufiicient fuel pressure to operate a shuttle piston 3b, which may becontained in a governor rotorplunger 31, through its full permissiblestroke for all desired engine speeds. Close control of pressure by theregulator 27 is unnecessary, for increasing the fuel pressure acting onthe hydraulically operated piston 3% beyond the minimum required to movethe piston through :its full stroke at maximum engine speed can notincrease the fuel delivery to injectors 32.

Fuel not bypassed by the regulator 27 passes through a conduit 33, ashutdown valve 34, and a branching conduit 35 to supply ports 36 and 37at the governor rotorplunger 31, which turns at crankshaft speed. Theshutdown valve 34 may be either a manually operated valve or an electricsolenoid valve.

Distribution of the Hydraulic Force to the Metering Mechanism and ofFuel to the Combustion Chamber (FIGS. 1 and 2) The rotor-plunger 33;admits fuel under pressure, first to a metering chamber 33 at one end ofthe shuttle piston 3i and then to a metering chamber 40 at the otherend, while the opposite end of the piston 3b is alternately connected todifferent injectors 32 (not all shown) in a timed sequence. A cycle ofoperations of the rotorplunger 31 and piston 3th will clearly illustratethis. In FIG. 1 a rotor port 41 in the rotor 31 is indexed with the port36, so that fuel under pressure can pass into the metering chamber 38formed between a fixed end wall 42 and one end of the piston 30 slidingin its bore 43. At the same time that the port 36 is indexed with therotor port 41, a rotor port 44 is indexed with an outlet port 45 leadinginto a conduit 46. A groove 47 in the rotor plunger 31 is connected tothe conduit 46 by a port 48 and also to a port S ll by an internalpassage 51 (shown dotted) and its outlet port 52, which serves as adistributor port. The outlet port 53 leads to the injector 32 via aconduit 53. Thus, when the rotor port d1 aligns with the pressure port36 and the rotor port 44 aligns with its outlet port 45, the fuelpressure in the chamber 33 pushes the piston 3i? to the right against afixed stop 54 and displaces the fuel in the chamber 4%) through theconduit 46, the rotor groove 47, the rotor passage 51 and the conduit 53to a fuel receiving chamber 49 in the mechanically actuated injector 32.(The injectors 32 all include fuel return lines 39 for carrying leakagefuel back to the fuel source or tank 20.)

In FIG. 2 the rotor-plunger 31 is shown turned through 130 to illustratehow the piston St is moved in the opposite direction to pump a fuelcharge to another injector 32 (not shown). Now, the rotor port 44 alignswith the pressure port 37, and the rotor port 4 aligns with an outletport 55, while the distributor port 52 aligns with an outlet port 56, sothat the chamber as is connected to pressurized fuel, and so that thechamber 38 is connected by a conduit 57 with the fuel receiving chamber49 of a second injector, and so that the fuel charge in the chamber 33is pumped to the fuel receiving chamber of that second injector.

The fuel supply system shown in FIGS. 1 and 2 with two injectors (onenot shown), and with the governor rotor 31 turning at crankshaft speeddelivers two measured charges of fuel per revolution of the rotor 31.This combination of two distributor ports opening onto a rotor runningat engine speed supplies the correct number i of fuel charges for atwo-cylinder, two-cycle engine. It is also easily possible to use thissame rotor-plunger 31 for a four-cylinder, four-cycle engine in whichfour mechanically actuated injectors are employed. Then, however, twoinjectors must be paired as described below in connection with FIG. 3.

A Simplified Device (FIG. 3)

If the fuel system is to be employed on a two-cylinder, two-cycle engineonly, the rotor-plunger 31 may be simplified as shown in FIG. 3. With amaximum of two injectors, and with the rotor still turning at crankshaftspeed, the outlet ports and now remain permanently connected to aconduit 69 leading to two paired injectors 32, with a delivery port 59adjacent to the fuel receiving chamber 49 in one of the paired injectors32, cut oil whenever the port 59 in the other injector 32a is open toits fuel receiving chamber 49. The rotor conduit 51, the distributorport 52, and the extra pump outlet 57 have thus been eliminated. Byreducing the speed of the rotor 31 to one half engine speed, theconstruction of FIG. 3 may be used for a single cylinder, two-cycleengine or a two-cylinder, four-cycle engine with the two injectorspaired. The operation of the piston 36, with its supply and outletports, is unchanged from that described for FIGS. 1 and 2, i.e., twofuel charges are pumped per one complete revolution of the rotor 31,regardless of the ratio of rotor speed to engine speed and whether theinjectors are or are not paired.

Determination of Volume of Fuel Charge Delivered to Injectors (FIGS. 13)

' forming the endwall of the bore 4-3 in the rotor-plunger 31, and thestop 54 on one end of a plug 61 permanently inserted into the rotor 31to form the endwall of the chamber 4% Changing the distance between thestop a 54- and a locating shoulder 62 on the end of rotor 31 is all thatis required to alter the maximum stroke of piston 36?, and, in turn, themaximum output of the engine. This alteration in length, accomplished bychanging the length of projection of the stub end 54 on the plug 61, canbe made only by the engine builder at the time of the pumps manufacture,and thus effectively prevents any unauthorized tampering with themaximum fuel delivery to the injectors. More importantly, for a seriesof engines requiring the same basic rotor construction, the identicalrotor-plunger 31 and piston 39 can be utilized. Only the simple plug 61need be different. This interchangeability of parts effects a great costsavings in the manufacture of the pump.

l dezhod of Throttling and Controlling the Idle and Overspeed (FIGS. 1and 4) Throttling and governing of idle and overspeed are controlled bythe interaction of three elements to change the axial position of thegovernor rotor-plunger 31 in its bore (FIG. 1). Centrifugal governorweights 63 are keyed to the rotor-plunger 31 and both rotate it and pushit to the right (in FIGS. 1-5) with an increasing force as the enginespeed increases. Counterbalancing the governor weight force to the rightare a pair of springs, namely, an idle control spring 64 and a maximumspeed control spring as, positioned between the plug 61 in the end ofthe rotor 31 and a lever 66 fastened to a manually operated throttleshaft 67 and in sliding contact with a rear spring guide 68. With thisgovernorthrottle combination the piston between its fixed end stops '52to the outlet ports and 55 a and 54 and discharges charge of fuel forfull 3t) always reciprocates load conditions. Control for any conditionless than a maximum charge delivery is achieved by returning theundesired volume to the suction side of the pump 24. Thus at an engineidle speed most of the charge is spilled off; at full load (wide openthrottle) none is spilled off; and at over speed the entire charge isreturned to the suction side of the pump'Z i. The percentage of fuelcharge spilled awayis determined by the axial position of therotor-plunger 31, and this axial position is a function of the positionof the throttle lever 66 and of the speed-responsive force of thegovernor weights 63 opposing the throttle-cam-varied forces of thesprings 64 and 65.

In FIG. 1, the throttle shaft 67 is shown in its full throttle position,and the rotor-plunger 31 is so positioned that the entire charge pumpedby the piston 36 is delivered to an injector. In FIG. 4, the throttle 67is shown in the closed position, and the rotor-plunger 31 is axiallylocated where a shoulder 70, on the right (FIGS. 1-5) edge of the groove47, uncovers a spilloff port 71 leading into a conduit 72. The conduit72 returns the fuel spilled off through the port 71 back to the conduits28 and 23 and to the suction side of the pump 24.

While the primary applicationof the fuel system is intended to be formarine service, the system can be used on an engine in any type of duty.Therefore, the four basic axial positions of the rotor 31 will bedescribed. These are for idling speed, coasting, overspeed, and fullload at any speed.

During the idling cycle of the engine the weak spring 64, encased in itsguide 73, counterbalances the opposing force of the weights 63. For agiven idle spring force the speed of the engine is determined by theaxial position of the shoulder 76. If the engine speed increases, theweights 63 move the rotor '31 to the right, causing the shoulder 7%) touncover more of the port 71. Less fuel is then delivered to theinjectors 32 because of the increased spillofl; so the engine speeddrops. The spilloff port area is then, in turn, reduced, and the enginespeeds up once more. The rotor-plunger 31 quickly reaches an equilibriumposition, and the engine idles at a substantially constant speed.

To increase, for example, the idle speed, the position of an adjustingscrew '74, limiting the angular movement of the shaft 67 in onedirection, is altered so that the lever 66 can move the rear guide 68slightly to the left. At low engine speeds the stiff spring 65 isessentially uncompressed and serves only as a spacer. The lever 66,acting through the guide 68, the spring 65 and an idle spring stop 75,directly controls the static compressive loading on the idle spring 64.With more initial squeeze now on the spring 64, the rotor-plunger 31 isforced to the left and reduces the spilloff to the pump suction. Enginespeed then increases, and the governor weights 63 soon position therotor-plunger 31 in a new equilibrium position which is slightly to theleft of its previous position before the adjustment was made. The finalamount of the rotor shift to the left is somewhat less than the shift ofthe lever-actuated guide 68, since the increased governor force at thehigher speed tends to compress the spring 64 slightly more than at thelower idle speed.

Whenever a load drives the engine, as in a vehicle coasting down hill,all fuel flow to the injectors 32 is stopped, by spilling off even theidle charge to the suction side of the pump 24. With the throttle shaft67 in its idle position, the governor force is strong enough to positionthe rotor 31 where it causes the entire fuel charge to spill through theport 71 whenever the engine is above an idle speed and the load isrotating the engine.

As the throttle shaft 67 is rotated away from the idle speed stop 7-5,or as the engine speed exceeds a fast idle, the weak spring 64collapses, and the forward guide 73 makes contact with the idle springstop 75. The spring 64- no longer has control over engine speed.

Rotating the shaft 67 has the net effect of positioning the governorrotor 31 further to the left in exactly the same manner as was describedfor the adjustment of the idle speed. While in the idle speed range, thespring 65 could be considered at its free length, but now it begins toshorten as the engine speed increases to the normal operating range. Asthere was no measurable preload on the spring 65' at idle, it collapsesat a rate directly proportional to its compressive force. This force,applied by the weights 63 on the end of the rotorplunger 31 increases ata rate proportional to the square of engine speed. Therefore, in orderto prevent any spilloif at the engines maximum rated speed at full load,the movement of the lever 66 must be enough to keep the shoulder 76 onthe rotor-plunger 31 from uncovering the port 71 even though thegovernor weight force has reduced the effect of this movement by theamount of deflection of the spring 65.

The maximum governed speed of the engine is determined by the strengthof the spring 65 and by a second throttle adjusting screw 76. The screw76 only provides a fine adjustment over a very limited speed'range. Ifthe throttle is in its fully open position and the engine should beginto speed up due to a decrease in load, the governor force overcomes thepredetermined maximum spring force and moves the rotor-plunger 31 touncover the spill port 71 and divert the fuel charge, dependent onengine load, to maintain the engine at its maximum governed speed. Ifthe load is further decreased,more fuel is spilled, etc.

One of the features of this governor, a modified form of a variablespeed governor, is that the engine will also self-govern at any speedbelow its maximum rated speed. For example, if the rated full-load speedis 2,100 r.p.m., and the engine is operating a piece of equipment at apart-load speed of 1,800 rpm, it is unnecessary to touch the throttleshaft to maintain a constant speed if the load on the engine shouldsuddenly increase. As soon as the governor weights 63 sense a drop inspeed, their force lessens and the spring 65 pushes the rotor-plunger 31to the left and reduces the volume of fuel spilled off. Speed then isreturned to the original 1800 rpm. As long as the ability of the engineto maintain this new load is not exceeded (determined by the stroke ofthe piston 3%), the engine speed will remain constant within a fewpercent. This degree of regulation thus makes the fuel supply systemapplicable for electric power generation.

This form of governor also lends itself to marine use, because the fueldelivered to the injectors is automatically reduced if the boatspropeller should lift out of the water as in a heavy sea or if, with anoutboard engine, the propeller should be knocked out of the water whenhit by an obstruction. The self-regulating speed feature under asuddenly decreased load works on the same principle but conversely tothat described above for a suddenly increased load. With the throttleheld constant, an increase in engine speed due to a load decrease causesa rotor shift to the right and more fuel spills off through the port 71.Obviously this feature applies to any variable load application where aconstant speed must or should be maintained regardless of the loadapplied to the engine.

Method of Fuel Distribution by Adams of a Distributor Rotor Synchronizedwith the Governor Rotor-Plunger (FIGS. 5 and 6) In FIGS. 5 and 6 I showa modification to the fuel supply system of FIGS. 1-4, whereby thesystem becomes adaptable to any multi-cylinder diesel engine usingmechanically actuated injectors. The governor rotorplunger 31 nowrotates at a multiple of engine speed, and the piston 3%) pumps the fuelcharges to a distributing rotor 89 which distributes them to theinjectors in a timed sequence. The rotor Si) is inside a housing dl andturns at crankshaft speed for a two-cycle engine and at one half speedfor a four-cycle engine. However, the speed of the rotor-plunger 31 is afunction of the number of engine cylinders in addition to the cycle.This ratio is fixed by the gears 78 and '79. For example, a sixcylinder, four-cycle engine requires three fuel charges per enginerevolution. Therefore, the rotor-plunger 31, which delivers two chargeseach revolution, must turn at one-and-one-half times engine speed topump the three charges per crank revolution. The fuel charge is pumpedfrom either chamber 33 or 46 through the conduit (it) to a groove 32 onthe rotor fit). It then travels upward through a rotor passage 83,leading to a distributor port 84, which aligns with one of the radialdischarge ports 85 and then into an outlet conduit 35 leading to aninjector 32. Next, the governor rotor-plunger 31 rotates 180 and thedistributor rotor 80 rotates 66 connecting the port 84 with another port87, next with a port 88, then with a port 89, then with a port 959, andfinally with a port 91. In one complete revolution of distributor rotor80 a fuel charge is delivered to each of the six injectors in the firingorder sequence, for example, 1-5-3-6-2-4 in FIG. 6.

If the modification of FIGS. 5 and 6 is adapted to an eight-cylinder,four-cycle engine the rotor-plunger 31 would turn two times engine speedto deliver four fuel charges per crank revolution. Also, the distributorhousing 81 would necessarily contain eight radial discharge outlet portsrather than the six as shown in FIG. 6. If a six-cylinder, two-cycleengine were to use this fuel supply system (six fuel charges per crankrevolution), the governor rotor-plunger 31 would need to turn threetimes engine speed. Pairing the injectors would reduce the number ofports by one half. Thus by the proper number of distributor ports androtor speeds the system is readily adaptable to multi-cylinder dieselengines of both two and four-cycle design.

The System With the Rotor-Plunger in a Housing Separate From theRotor-Plunger (FIG. 7)

While the piston 39 is shown in FIGS. 1-5 operating between fixed stopswithin the rotor-plunger 31, it should be understood that it is notnecessary for the rotor 31 to contain piston 30. By making additionalports in the housing and rotor, the piston 39 can just as well becontained in the housing adjacent to the rotor. Control by the throttleshaft 67 and governor weight 63-springs d4, 65 combination are identicalfor either piston location.

In FIG. 7, fuel under pressure in the conduit 35 is conducted to thechamber 4% by an angling conduit 1% in a new plunger-rotor I191, whichconnects the port 3'7 to a rotor port M52 at one end of a branchingconduit 193. At the same time, another angling rotor conduit 1M connectsa rotor port 1695 to a port 1%. The fuel charge is then pumped from thechamber 38 through a second branching conduit M97, the rotor conduit 1%,a third branching conduit 163 and to a port 1169 leading into the groove47 on the plunger-rotor 131. The fuel is then conducted to an injectorthrough the conduit 60 as before. The position of the shoulder 79,controlling the area of the port 71, determines the volume of chargespilled ed and returned to the suction side of the pump 24 through theconduit 72. When the rotor fill is rotated 180, the angling conduit 1Mconnects a port 111 on the conduit 197 With fuel under pressure at theport 36, and the angling conduit litl connects a port 112 on the conduit1% with a port 113 on the conduit 1%. The piston St is then forced tothe right" by pressurized fuel entering the chamber 38, and the fuel inthe chamber 40 is pumped to an injector through the newly connectedconduits 193, lltlil, 103 and so.

Prevention of Overfueling Upon Sudden ll lovement Throttle to MaximumPosition (FIG.

If the throttle 67 is rotated suddenly from a part throttle position,corresponding to light load and low engine speed, to a full throttleposition, it may be desirable in some applications to add a control toprevent momentary overfueling and/ or overloading of the engine. Thiscontrol is provided by the addition of a small spillotf port 92 and aconnecting conduit 3 leading into the return conduit 72, as seen in FIG.5. Normally, when the throttle is rapidly opened at a low engine speed,the rotor-plunger 31 is shifted leftward, with the shoulder 7%)completely cutting off the port 71, so that the maximum fuel charge isdelivered to the injectors momentarily. The governor weights 63 in thelower speed ranges do not have enough force to prevent this entireshutoff of the spill port 71. However, by means of the spill port 92,this transient overloading condition can not occur. When the suddenshift takes place, a left shoulder 94 of the rotor groove 47 uncoversthe port 92 and spills off part of the charge. As the engine speedincreases, the larger governor force causes the shoulder 94 to graduallyclose off the port 92 and let more of the fuel charge pass to theinjectors. By the time the port 92 is completely cut off, the speed ofthe engine has reached the point where a maximum fuel charge will notcause overloading. If the engine is operating in the higher speed rangesand the throttle shaft 67 is suddenly rotated to its maximum position,the shoulder 94 never uncovers the port 92 because the governor force isstrong enough to prevent such a large leftward shift of therotor-plunger 31. This is permissible because the engine can now absorbits maximum fuel charge without being overloaded. If the operatorapplies the throttle moderately, the spill port 92 is not uncovered evenat low engine speeds.

Summary of Operation Fuel under pressure from the gear pump 24 isalternately directed into the metering chambers 38 and 40 at theopposite ends of the shuttle piston 30. When the fuel pressure is actingon one end of the piston 30, the chamber at the opposite end isconnected to the fuel receiving chamber 49 of an injector 32. Thesecondary distributor rotor of FIGS. 5 and 6 is used if necessary toaccommodate any multi-cylinder engine.

The metering piston 30 shuttles between the fixed stops 42. and 54, itsfull stroke determining the maximum desirable fuel charge. Duringpart-throttle, idle and overspeed conditions, the unwanted portion ofthe fuel charge is returned to the suction side of the pump 24 throughthe port 71. The force due to the governor weights 63 is counterbalancedby the force of the springs 64 and 65, in conjunction with the throttle67, to axially position the rotor-plunger 31 and in turn the spillotfcontrol shoulder 70.

In a multi-cylinder engine the additional injectors are supplied by thesame rotor design by changing the speed of the rotor 31. The ratio ofrotor speed to engine speed is a function of the number of enginecylinders and of type of cycle, either two or four.

Control of Runaway A very important advantage obtained by adopting thisform of overspeed control is the prevention of the engine from runningaway if the suction line 21 between the tank 21) and gear pump 24 shouldrupture or if the tank should become empty while the engine is running.Without some form of runaway control a diesel engine can destroy itselfunder these conditions by overspeeding. This occurs if any significantamount of air fills the supply passages between the governor rotor 31and the injectors 32. For all practical purposes fuel oil isincompressible, and under normal conditions the fuel in the supplypassage is batched through by a new slug pumped either from the meteringchamber 38 or 40 (FIGS. 1-5). But air is highly compressible and willcontinue to force fuel to the injectors in a manner similar to apneumatic ram as long as the injector plunger supply port 59 indexeswith passages leading to the plunger chamber 49 (FIGS. 1 and 3). Thus,many times the fuel charge required will be injected into the enginecausing an extremely rapid acceleration of the engine to speeds whichare destructive. The engine will only slow down When the expanding airbehind the column of fuel in the lines to the injectors has shoved allof the fuel into the plunger chambers and then injected into the engineor when the engine has destroyed itself. Even with the engine underheavy load there is a period of uncontrolled high speed, although not asdangerous as when under light load. By opening one end of the conduitsbetween the governor rotor 31 and the injectors 32 to the suction sideof the pump 24, any air which should pass into the conduits 53 (FIG. 1)or 60 (FIGS. 3, can be sucked back to the supply pump 24 and eliminatethe possibility of the pneumatic ram effect. At the same time the aircan no longer be effectively pumped by the shuttle piston 34 because therotor ports 41, 44 have almost passed out of index with their connectingfuel supply ports 36 and 37. The engine simply comes up to governedspeed and remains at that speed until all of the fuel in the lines hasbeen burned with no harm to the engine.

To those skilled in the art to which this invention relates, manychanges in construction and Widely'differing embodiments andapplications of the invention will suggest themselves Without departingfrom the spirit and scope of the invention. The disclosures and thedescription herein are purely illustrative and are not intended to be inany sense limiting.

I claim:

1. In a fuel system for use with a compression ignition engine havingfuel injectors, said system having a housing with a bore having fixedstops, a shuttle piston in said bore, with its ends defining first andsecond ported chambers, one in each end of said bore between said pistonand said fixed stops, means for charging fuel under pressure from a fuelsource to each said chamber alternately, thereby to move said shuttlepiston a fixed stroke and discharge fuel from the opposite chamber, andconduit means for connecting each said chamber at discharge to a fuelinjector on the engine,

the combination therewith of:

speed-responsive means in said conduit means for reducing the amount offuel delivered to said fuel injector at predetermined engine speeds bysaid shuttle piston at discharge, Without affecting the fixed stroke ofsaid shuttle piston.

2. The system of claim 1 having a manually controlled throttle, and

yieldable means connecting said throttle to said speedresponsive meansfor varying the effect thereof on the fuel delivered to said fuelinjector according to the position of said throttle.

3. The system of claim 2 having additional means for reducing the amountof fuel delivered to said fuel injector by said shuttle piston atdischarge, said additional means being actuated by said yieldable meansovercoming said speed-responsive means at low engine speeds.

4. The system of claim 1 in which each fuel injector is adjacent acombustion chamber and includes a fuel injector housing having a boretherein,

a plunger reciprocable in said bore,

a fuel-receiving chamber formed in said bore upon retraction of saidplunger, and engine timed means for moving said plunger in said bore toinject the fuel from said fuel-receiving chamber into said combustionchamber, and in which the means connecting each said ported chamber atdischarge to a fuel injector includes a conduit connected at one end tosaid ported chamber and at its other end to two or more of said fuelinjectors which inject fuel at different times from each other, and

means synchronizing said shuttle piston movement and the metering offuel thereby with the means for moving said plungers of said injectors,

whereby said reciprocable plunger in each of said fuelinjector housingscontrols the time of deposit of fuel in each thereof from said portedchamber and functions as part of the fuel distributing mechanism for theengine.

5. The system of claim 1 as applied to a four-cycle engine and in whicheach fuel injector is adjacent a combustion chamber and includes afuel-receiving chamber,

a plunger mechanically actuated in said fuel-receiving chamber to forcea fuel charge pumped to said fuelreceiving chamber into said combustionchamber,

a single conduit connecting a said ported chamber at discharge to aselected pair of fuel injectors, which inject their charge of fuel atdifferent times so that when the passage to the fuel-receiving chamberin one is open, the other is closed, and

means synchronizing said shuttle piston movement with the means formoving said plungers of said injectors,

whereby said injector plungers function as part of the fuel-distributingmechanism for the engine.

6. In a fuel system for use with a compression ignition engine with fuelinjectors and a governor, said system having a housing with a borehaving limiting members fixed at each end, a shuttle piston in said borebetween said fixed limiting members, with its ends and said limitingmembers defining first and second ported chambers, one in each end ofsaid bore, a fuel reservoir, a fuel pump having a suction side connectedto said reservoir, means for charging the fuel under pressure from saidfuel pump to each said chamber alternately, thereby to move said shuttlepiston a fixed stroke and discharge a fixed volume of fuel from theopposite chamber, and conduit means for connecting each said chamber atdischarge to a fuel injector on the engine,

the combination therewith of:

spill-off means in said conduit means controlled by said governor forreducing the amount of fuel delivered to said fuel injector atpredetermined engine speeds by returning a controlled portion of thefixed volume of fuel from the discharging chamber to said suction sideof said fuel pump.

7. The system of claim 6 having a manually controlled throttle, and

spring means connecting said throttle to said governor controlled meansfor partially overcoming the fuel reducing effect of said governorcontrolled means by an increase in throttle opening.

8. In a fuel system for use with a compression ignition engine with fuelinjectors and a governor, said system having a housing with a borehaving limiting members fixed at each end, a shuttle piston in said borebetween said fixed limiting members, with its ends and said limitingmembers defining first and second ported chambers, one in each end ofsaid bore, a fuel reservoir, a fuel pump having a suction side connectedto said reservoir, means for charging the fuel under pressure from saidfuel pump to each said chamber alternately, thereby to move said shuttlepiston and discharge fuel from the opposite chamber, and means forconnecting each said chamber at discharge to a fuel injector on theengine,

the combination therewith of:

means controlled by said governor for reducing the amount of fueldelivered to said fuel injector'at predetermined engine speeds byreturning a controlled portion of the fuel from the discharging chamberto said suction side of said fuel pump,

a manually controlled throttle,

spring means connecting said throttle to said governor controlled meansfor partially overcoming the fuelreducing effect of said governorcontrolled means by an increase in throttle opening,

said spring means acting on said governor controlled means to preventsaid reduction of fuel and said return of fuel at speeds below a firstpredetermined speed when said throttle is wide open, and

second means for reducing the amount of fuel delivered to said fuelinjector by returning a second controlled amount of said fuel from saiddischarging chamber to said suction side of said pump,

said second means being actuated by said spring means overcoming theaction of said governor at fully open throttle at speeds below a secondpredetermined speed lower than said first predetermined speed.

9. The system of claim 6 in which each fuel injector is adjacent acombustion chamber and includes a fuel injector housing having a boretherein,

a plunger reciprocable in said bore,

a fuel-receiving chamber formed in said bore upon retraction of saidplunger, and

engine-timed means for moving said plunger in said bore to inject thefuel from said fuel-receiving chamber into said combustion chamber, and

in which the means connecting said discharging ported chamber to a fuelinjector includes a conduit connected at one end to said dischargingported chamber and at its other end to two or more of said fuelinjectors which inject fuel at different times from each other, and

means synchronizing said shuttle piston movement and the metering offuel thereby with the means for moving said plungers of said injectors,

whereby said reciprocable plunger in each of said fuelinjector housingscontrols the time of deposit of fuel in each thereof from saiddischarging ported chamber and functions as part of the fueldistributing mechanism for the engine.

10. The system of claim 6 as applied to a four-cycle engine and in whicheach fuel injector is adjacent a combustion chamber and includes afuel-receiving chamber,

a plunger mechanically actuated in said fuel-receiving chamber to forcea fuel charge pumped to said fuelreceiving chamber into said combustionchamber, and

a. single conduit connecting said discharging ported chamber to aselected pair of fuel injectors, which inject their charge of fuel atdifferent times so that when the passage to the fuel-receiving chamberin one is open, the other is closed, and

means synchronizing said shuttle piston movement and the metering offuel thereby with the means for moving said plungers of said injectors,

whereby said injector plungers function as part of the fuel-distributingmechanism for the engine.

11. The system of claim 6 wherein one of said limiting members isreplaceable by like members of different length to change the maximumstroke of said piston and thereby change the maximum fuel output of saidsystem;

12. In a fuel system for use with a. compression ignition engine withfuel injectors, said system having a housing with a bore, a shuttlepiston in said bore,

with its ends defining first and second ported chambers, one in each endof said bore, a fuel source, a fuel pump having a suction side connectedto said fuel source,

first conduit means for charging fuel under pump pressure to each saidchamber alternately, thereby to move said shuttle piston and dischargefuel from the opposite chamber, and second conduit means for connectingeach said chamber at discharge to a fuel injector on the engine,

the combination therewith of:

fixed stops for determining the extent of movement of the shuttle pistonin each direction, so that said shuttle piston has a constant stroke inboth directions,

engine-speed responsive means,

a plunger-rotor rotating at a speed synchronized with the speed of theengine to open and close alternately the connection to each said chamberfrom said fuel pump via said first conduit means, and alternately toopen and to close said second conduit means from each said chamber, allin synchronism with said fuel injectors, and

third conduit means for returning spilled-off fuel from said chambers atdischarge to said suction side, when connected to said chambers,

said plunger-rotor being connected at one end to said engine-speedresponsive means for moving axially toward its other end under controlof said enginespeed responsive means to connect the discharging chamberto said third conduit means and thereby reduce the mount of fueldelivered to said fuel injector at predetermined engine speeds.

13. The system of claim 12 having I a manually controlled throttle leveradjacent the other end of said plunger-rotor and spring means betweensaid other end and said lever opposing the axial movement of saidplunger-rotor toward said other end when so urged by said enginespeedresponsive means,

so that movement of said throttle lever against said spring meansincreases the resistance thereof to movement of said plunger-rotortoward said other end and consequently the resistance to the reductionin the amount of fuel delivered to said fuel injector.

14. The system of claim 13 having fourth conduit means for theprevention of overfueling at low engine speeds by return to said suctionside of a fraction of the fuel being discharged from said chambers,

said plunger-rotor having means for connecting said fourth conduit meansto said chambers at discharge at times when said spring means hasprevented connection of said third conduit means to said chambers atdischarge due to the engine speed being lower than a first predeterminedspeed at which said enginespeed-responsive means causes saidplunger-rotor to connect said third conduit means at discharge and when,in addition, said engine is under substantially full throttle and at asecond predetermined speed slower than said first predetermined speed.

15. The system of claim 13 wherein said spring means comprises twosprings in series, one of said springs being a light spring used foryielding readily under idling conditions of the throttle and the other arelatively stiff spring yielding less readily.

16. The system of claim 12 wherein said housing is part of said rotorplunger, with the bore in said rotor plunger and said shuttle pistonmoving therein.

17. The system of claim 12 wherein said housing is a stationary memberseparate from said plunger-rotor.

18. The system of claim 17 wherein the plunger-rotor has a pair ofconduits with axially offset ends that perform the opening and closingof the connection to said chambers of said first and second chambers, inalternation, each rotor conduit first connecting one of said portedchambers to said first conduit means and, second, half a revolution ofsaid plunger-rotor later, connecting that said ported chamber to saidsecond conduit means.

19. In a fuel system for use with a compression ignition engine withfuel injectors, said system having a fuel source and a fuel pumpconnected to said fuel source,

the combination therewith of:

engine-speed responsive means,

a plunger-rotor rotating at a speed synchronized with the speed of theengine and moving axially under control of said engine-speed responsivemeans, said 13 plunger-rotor having a bore therein and stationary endsfor said bore,

a shuttle piston in said bore, with its ends and the bore ends defininga ported chamber in each end of said bore,

conduit means for charging fuel under pump pressure to each chamberalternately, thereby to move said shuttle piston a fixed stroke and todischarge a fixed volume of fuel from the opposite chamber, and

a conduit means for connecting each said chamber at discharge to a fuelinjector on the engine,

the rotation of said plunger-rotor opening and closing the connectionfrom said fuel pump by said conduit means for charging fuel to each saidchamber alternately, to open and to close the conduit means from 15 14each chamber to fuel injectors alternately, all in synchronism with saidfuel injectors, and the axial movement of said plunger-rotor controllingthe amount of fuel delivered to said fuel injectors at predeterminedengine speeds.

References Cited in the file of this patent UNITED STATES PATENTS2,053,543 Vincent Sept. 8, 1936 2,110,405 Starr Mar. 8, 1938 2,312,212Edwards Feb. 23, 1943 FOREIGN PATENTS 980,257 France Dec. 27, 1950

1. IN A FUEL SYSTEM FOR USE WITH A COMPRESSION IGNITION ENGINE HAVINGFUEL INJECTORS, SAID SYSTEM HAVING A HOUSING WITH A BORE HAVING FIXEDSTOPS, A SHUTTLE PISTON IN SAID BORE, WITH ITS ENDS DEFINING FIRST ANDSECOND PORTED CHAMBERS, ONE IN EACH END OF SAID BORE BETWEEN SAID PISTONAND SAID FIXED STOPS, MEANS FOR CHARGING FUEL UNDER PRESSURE FROM A FUELSOURCE TO EACH SAID CHAMBER ALTERNATELY, THEREBY TO MOVE SAID SHUTTLEPISTON A FIXED STROKE AND DISCHARGE FUEL FROM THE OPPOSITE CHAMBER, ANDCONDUIT MEANS FOR CONNECTING EACH SAID CHAMBER OF DISCHARGE TO A FUELINJECTOR ON THE ENGINE, THE COMBINATION THEREWITH OF: SPEED-RESPONSIVEMEANS IN SAID CONDUIT MEANS FOR REDUCING THE AMOUNT OF FUEL DELIVERED TOSAID FUEL INJECTOR AT PREDETERMINED ENGINE SPEEDS BY SAID SHUTTLE PISTONAT DISCHARGE, WITHOUT AFFECTING THE FIXED STROKE OF SAID SHUTTLE PISTON.